- Add AMFClient and ES2Service dependencies to SubscriberService
- Initialize AMF client with default URL and ES2 service in NewSubscriberService
- Implement provisionESIMProfile with EID validation, profile provisioning, activation, and AMF notification
- Implement deactivateESIMProfile with profile deactivation, status updates, and session termination
- Add generateOPc helper for deriving OPc from OP and K using XOR-based
- Add AMFClient struct with base URL and HTTP client
- Add NewAMFClient with 30s timeout
- Add TerminateSession for subscriber session termination with reason and timestamp
- Add NotifySubscriberUpdate for subscriber status change notifications
- Add SessionTerminationRequest and SessionTerminationResponse models
- Add generateRequestID helper for request tracking
- Add ES2Service struct with HTTP client and ES2Config
- Add NewES2Service with 30s timeout and TLS configuration
- Add ProvisionProfile for eSIM profile provisioning with metadata support
- Add ActivateProfile, DeactivateProfile, and DeleteProfile for profile lifecycle management
- Add GetProfileStatus for profile state queries
- Add ListProfiles for eUICC profile enumeration
- Add ValidateEID and ValidateICCID for identifier
- Add SubscriberService struct with Database and Config dependencies
- Add NewSubscriberService constructor
- Add CreateSubscriber with IMSI allocation, auth key generation, and eSIM provisioning support
- Add GetSubscriber and GetSubscriberByIMSI for subscriber retrieval
- Add UpdateSubscriber for subscriber information updates
- Add SuspendSubscriber with session termination
- Add TerminateSubscriber with session termination and eSIM profile deactivation
- Add ListSubscribers with pagination and